On my 03 excursion v-10 4x4 4r100 automatic I'm having a little problem. The tranny has been working fine. No heat, No slippage, No stink. It was pulling 24 foot wakeboard boats up out of the boatramp with no issues at all. We dropped a boat off at my shop backed it in, unhooked, pulled out of the building and parked with everything working perfect. Went inside and worked on the boat for an hour and had to go get some parts. So I go out side and fire up the excursion and pull it into gear and it would barely move. Like a manual tranny with a slipping clutch. Engine revs up and eventually it starts to move. Reverse works perfectly normal. So I just parked it for the day. Whenit was time to go home I decided to move it to the back storage lot for the night. I was kinda mad at it so when it started to slip I just Floored it and all of a sudden it grabed and started working normal. I even pulled a dry pavement donut to make sure it wasnt slipping. The next day i took it for a test drive and after 2-3 miles it started acting up again. My budy that works at the ford dealer hooked up some kind of computer to it and couldnt find anything. I dont know anything about automatics except one minute they work fine and the next they don't. lol